Degradation picks are known to be used in such fields as road milling, mining, and trenching to engage and degrade tough materials such as asphalt, concrete, and rock. In use, such degradation picks may be secured to an exterior of a rotatable drum or continuous chain so as to be repeatedly brought into contact with a surface of a material to be degraded.
Degradation picks are known to take several forms. One form of degradation pick, as described in U.S. Pat. No. 7,396,086 to Hall, et al., comprises a shank attached to a base of a steel body. A cemented metal carbide core may be press fit into the steel body opposite the shank. An impact tip, comprising a carbide substrate and a diamond material bonded to the substrate, may be bonded to the core opposite the shank. Additionally, the shank, carbide core and diamond material may be generally coaxial.
While this known arrangement may prove sufficient in some applications, it may also expose degradation picks to side impact forces which they may not be constructed to withstand. Specifically, impact testing has shown that axially symmetrical degradation picks experiencing impact forces at an angle greater than 35 degrees off axis fracture significantly more often than those experiencing axial impact forces.
Some forms of degradation picks, such as those commonly known as radial tools, are designed specifically to degrade a formation in a manner that the degradation pick experiences impact forces from an angle. For example, U.S. Pat. No. 8,789,894 to Lucek et al., describes a non-rotating mining cutter pick comprising a shank portion with a non-circular cross-section, a head portion including a tip region distal from the shank portion, and a cutting insert mounted at a front end of the tip region. The cutting insert is typically positioned on a forward working portion to cut into a mineral formation during operation. While the non-circular cross-section may restrict the mining cutter pick from rotating, it may only be used at one angle, which is the angle of the block used to support the radial tool.
Accordingly, a need exists in the art for a degradation pick assembly that allows a hardened tip to experience impact forces at an ideal angle while being able to be inserted into a block at multiple angles.